1. Field of the Invention
This invention is related to the field of use of image capture. More particularly, this invention is directed to a method and apparatus for signaling a still image capture during video capture.
2. Description of Related Art
Video capture using a digital camera attached to the personal computer (PC) has become very prevalent. Video capture may be used for such applications as video conferencing, video editing, and distributed video training. Many components of hardware and software need to work seamlessly to both get the video data (also referred to as a video xe2x80x9cstreamxe2x80x9d) from the hardware through the various layers of software on the PC and made visible on a display medium. Apart from displaying motion video, users usually also like the capability to capture a single frame of the video for further processing. This process is also known as capturing a still image from a video stream. The applications that can operate with data from or generate these video streams are commonly referred to as streaming applications.
Currently, the capture of such a still image may be accomplished using a xe2x80x9cpullxe2x80x9d mechanism, where an application initiates the process of capturing a still image. Typically, the application initiates the process after a user has used a graphical user interface, such as selecting a button or a menu command, or otherwise provided a command to the application indicating that the user wishes to capture a still image from the video stream.
The second mechanism, the xe2x80x9cpushxe2x80x9d mechanism, is where the hardware and lower layers of the software (e.g., a driver for the hardware), provides an indication to an application that the user intends to capture a still image. In this mechanism, a user would operate a switch on the digital camera that generates a signal to indicate an image capture is desired.
One way a still image could be captured from a video stream using the push method is by using a buffering mechanism. The buffering mechanism caches the data for the still image in the device driver and waits for an application to poll the driver periodically for the availability of such a still image. However, the implementation of this mechanism would involve the writing of a separate application that is capable of communicating with the device driver. In addition, a complex signaling system might be required for communicating information between the driver and the application once the still image is received by the hardware. Hence, in this implementation, the still image application becomes very customized to the driver, and is not easily portable to other devices that may require different drivers.
Thus, it is desirable to have a mechanism that assists common streaming applications to also act as a still image aware application.
A method comprising receiving a still image frame capture command in a push model mechanism; capturing an image frame; and, modifying a set of bits in an image plane in said image frame; wherein said set of bits in said image plane indicates that said image frame is a still image frame. An apparatus for performing the above method is also provided.